The present invention pertains to a sputtering cathode with a flat plate-shaped target formed from at least one part and a tub-shaped yoke arranged behind the target with a center ridge and with magnets for generating an enclosed tunnel of arc-shaped curved field lines in front of the target surface, as well as with three sheet metal cutouts or groups of partial cutouts of magnetically conductive material inserted into the plane between the target and the end faces of the tub rim of the yoke, wherein two of these sheet metal cutouts or groups of partial cutouts cover the area above the end faces of the tub rim and the center ridge and the third sheet metal cutout or the third group covers a part of the area between the end face of the center ridge and the end face of the tub rim and all the sheet metal cutouts together form two gaps extending roughly parallel to the end faces.
A sputtering cathode is known from U.S. Pat. No. 4,865,708, in which segments of permeable material are arranged between the target, on the one hand, and the magnet yoke, on the other, in the plane of the magnet rows, more particularly, underneath the plane of the front magnetic surfaces facing the target, in order to divert the tunnel of curved field lines forming in front of the target into a concave shape, in order to permit a wider erosion trench on the target and thus a longer target service life.
Furthermore, a sputtering cathode has been proposed in DE 196 22 606.6, with a basic cathode element with a plate-shaped target as well as with a magnet yoke arranged behind the target, with two closed rows of magnets of different polarization arranged in an oval or rectangular configuration and mutually coaxial in a plane parallel to the target. In this known device the sheet metal cutouts or appropriately configured partial cutouts of magnetically conductive material are inserted into the plane between the target and the end faces of the magnets turned towards the target, wherein two of the sheet metal cutouts or partial cutouts have a frame-shaped configuration. The two respective arc-shaped sections of the sheet metal cutouts connecting the long straight parts have an edge profile departing from the circular, for instance, elliptical, parabolic or irregularly arc-shaped, so that the respective gaps formed by two adjacent arc-shaped sections have an irregular width profile.
In addition to that, a sputtering cathode has been proposed in DE 196 22 607.4 with a magnet yoke arranged behind the target, with two rows of magnets arranged in an oval or rectangular configuration in a plane parallel to the target, with three sheet metal cutouts or group of partial cutouts inserted into the plane between the target and the end faces of the magnets facing the target. Two of these sheet metal cutouts or groups of partial cutouts cover the area above the magnets and the third sheet metal cutout or the third partial cutout cover part of the area between the magnets. All the sheet metal cutouts together form two gaps extending essentially parallel to the rows of magnets.
Accordingly, an object of the present invention is to arrange the magnets such that, on the one hand, a flat and particularly wide erosion trench forms during the sputtering operation and as optimal a removal of material from the target as possible results and, on the other hand, the area between the magnetic tunnels extending in parallel is formed as narrowly as possible.